Polyethylene terephthalate (also referred to as “PET”) is a polyester of terephthalic acid and ethylene glycol and can be obtained by the polycondensation of dimethyl terephthalate with ethylene glycol, and also terephthalic acid with ethylene glycol or ethylene oxide. PET exists both as an amorphous (transparent) and as a semi-crystalline (opaque and white) thermoplastic material. Generally, it has useful chemical resistance to mineral oils, solvents and acids but not to bases. Semi-crystalline PET has good strength, ductility, stiffness and hardness. Amorphous PET has better ductility but less stiffness and hardness. PET is used to make bottles for soft drinks and other household and consumer products. Unfortunately, despite recycling efforts, billions of pounds of PET are still dumped into landfills annually all over the world. Other PET that is not reused is incinerated. The substantial amount of PET that is disposed into landfills creates significant waste. The incineration of PET requires significant resources that could be used more effectively.
Thermoplastic molding compositions based on polybutylene terephthalate (also referred to as “PBT”) and epoxies are used in various applications. Although conventional PBT-epoxy molding compositions are useful to many customers, ordinary PBT-epoxy molding compositions generally cannot be made from recycle sources of PBT due to the lack of availability. PET, unlike PBT, is made in much larger quantities and is partially recovered from consumer wastes. If PET (scrap) materials could be converted to PBT and converted into useful molding compositions, then there would exist a valuable way to meet the unmet need to effectively use underutilized scrap PET in PBT thermoplastic molding compositions.